For the past two decades, those involved in teacher training have encouraged teachers to incorporate evidence from research into a process of critical reflection to improve the quality of their decisions. Using research as part of a deliberative reflective process has been thought to enable teachers to learn from their practice. However, teachers' decision-making has proven highly impervious to external influence. Teachers often resist reflective models that attempt to take their thinking to deeper, critical levels and are unlikely to use empirical evidence to inform their decisions. Given these conditions, this study seeks further insight into teachers' pedagogical decision-making amidst the complex dynamics of 'real-world' educational contexts. Based on a systematic review of over three decades of decision research, a questionnaire was developed to investigate the decision process of 80 pre- and in-service teachers working in the post-compulsory sector. Data were analysed to uncover how these teachers made sense of the range of information that came into play when deciding how to resolve a pedagogical issue and the sources they used to inform their decision-making. If those involved in pre- and in-service teacher training could build upon teachers' intrinsic decision processes, they could potentially support greater decision effectiveness.